This invention relates to an apparatus for adjusting the tension of a web material passing through a web-fed printing press, particularly a web-fed offset printing press.
Prior art apparatus of this type includes two parallel shafts, at least one of which can be rotatably driven, and four rings, with two of such rings being spaced apart and fixed to the ends of each shaft such that the web material passes through the gaps between the mutually facing rings. The tension of the web material is controlled, for example, by adjusting the rate of rotation of the shafts.